NEED HELP Battery Dead... but not.

[Roamingdoc]

9 month old battery. '02 4X TBlzr LTZ running well, 370K and doing fine.
2 weeks ago, in the garage, went to start and 'dead, dead, dead'. Not
even a click. Jumpered it, started quickly. V gauge was 14 and a bit...
carried cables around for past two weeks, never an issue. Two days ago
noted that the gauge was now in between 13 and 14 (these gauges aren't
the best anyway). Yesterday I went into the garage, got in and turned
the key (car in park) and it started right up but the 'blurb' warning in
red light above the shift location stated, "battery not charging" and
the little "battery" icon, upper right of speedo area, was present, lit.
It did start, quickly too. WHEN I PUT the shifter into Drive the
warnings ALL went away and never returned. Have had the 'battery'
checked, all good. The started, all good. Alternator, all good, recently
had major front end (upper and lowers, balls), of course Oil/Filter/Fuel
Filter and so forth. Chasing this has proven difficult as "it isn't
present" to show someone to trace. Appreciate any thought/input. Thank
you... see if I can post the photo.

 

[Mooseman]

I'd be checking all the grounds and battery connections. I also remember having something like this and it was the replacement alternator's connector that wasn't quite right and not letting the connector click/lock in place and it would work itself loose. So check that connector for any corrosion and the main battery power wire on the stud in the back of it.

And thinking back again, I once had a dying alternator that occasionally threw that message at me but would go away. Eventually it completely died but didn't take too long to happen. The dead battery could also point to a bad alternator if it has an internal short or diode failure allowing some parasitic power drain.

 

[Roamingdoc]

Agreed. First thing I did was check ground and battery connections, no rust, not loose. Alternator is accessible and I will double check (had it on the 'O'Reilly' tester for 15 minutes the other day, never a hiccup) WILL look at those places... the 'parastitic' power drain was the first thought when we found the car totally dead 2 weeks ago... am no longer able to crawl around so testing 'that' can be irksome, will see if my mechanic wants to. Many thanks MM... been a while, good to see you are still active.

 

[c good]

Mine looked fine from the outside. I put on a new cable and it solved my intermittent starter problems.

 

[Roamingdoc]

Yeah, that looks rough. Will double check but the original cables were replaced over time with new ones, so many miles... cables on the back of the alternator, will check. Thank you.

 

[mrrsm]

Visit THIS Thread...and Review it with...Or Pass It On to your Mechanic:

Electrical Ground locations

While troubleshooting a bad ground I came across some scans of the service manual regarding electrical ground locations for our platform posted on another site. This includes both short and long wheel base, as well as both 4.2L and 5.3L. Credit goes to Wex...

gmtnation.com

Replacement OEM Quality Positive and Negative Cables:

2002 CHEVROLET TRAILBLAZER 4.2L L6 Battery Cable | Shop Now at RockAuto

Electrical Parts and More for Your 2002 CHEVROLET TRAILBLAZER at Reliably Low Prices. Fast Online Catalog. DIY-Easy. Your Choice of Quality. Full Manufacturer Warranty.

www.rockauto.com

Electrical Grounds PDF Courtesy @jmonica via @Realism 's Epic Grounds Thread:

PS: Check BOTH the Under-hood Power Distribution Center Fuse Blocks AND the Rear Fuse Blocks for ANY Burned Out Fuses.

 

[Roamingdoc]

Thank you, knew the location of the fuse boxes... BUT holy cow, did not know all those ground.
UPDATE:
FINAL report... sorta knew it was going here. First, my mechanic is a solid, well certed and experienced fellow. He has a 3 lift garage and two other mechanics and one sort of 'gopher'. He's late 40s and has been around. He loves electrics. When we took it in, he said, "Hey, no problems, we'll figure it out"... we are friends and I said, "I hope it is obvious"... it wasn't and he charged us very minimal for what had to have been several hours of diagnostics, etc... the end result. "It was a gremlin, they exist and like to stay hidden to the most inopportune time..." Kevin is a fabulous guy, I trust him. There is not follow up, if he couldn't figure it out I have to accept it. The TBlzr has been perfect, absolutely perfect. It has all these miles on it and runs so well. He said he'd keep it always in the back of his mind when we bring it in for normal servicing and do a quick check so something won't obviously sneak up on us..but. And so it goes. Wish I had a 'great fix' to report, but all I have, it seems, is a 'great little SUV' that keeps on running. Thanks for all the good ideas and support, sorry I cannot reciprocate with a 'solid' fix.

 

[c good]

Check the main ground to the PCM. It's a spade type connector. Mine was loose and world cause intermittent problems as you described.

 

[c good]

This center post is ground

 

[c good]

This center post is ground